I had just seen this for the first time and beat tracks over here to repost it but you beat me to it. It appears to me that he has a lot less weight on the truck that a lot of drivers do pulling "legal" loads. I wish the pictures were better I'd like to see how he set up his air brake system!!!! It looks interesting to say the least.
2011 GMC Sierra 2500 HD 2500 4X4 Duramax Traded 162,000 miles!!
2019 GMC Sierra 3500 HD CC 4X4 Duramax SRW LWB Stone Blue Metallic